Many satellites and other spacecraft, as well as some terrestrial stationary and vehicle applications, such as seagoing vessels, can include one or more energy storage flywheel systems to provide both a backup power source and to provide attitude control for the vehicle. In such vehicle applications, each energy storage flywheel system is controlled and regulated to balance the electrical demand in the vehicle electrical distribution system, and may also be controlled in response to programmed or remote attitude (or torque) commands received by a main controller in the vehicle.
In many instances an energy storage flywheel system includes one or more components that are rotationally mounted within a housing. These components, which may be referred to as the rotating group, include, for example, an energy storage flywheel, a motor/generator, and a shaft. The energy storage flywheel and motor/generator may be mounted on the shaft, which may in turn be rotationally mounted in the housing via one or more bearing assemblies. In many instances, the shaft is rotationally mounted using one or more primary bearing assemblies, and one or more secondary, or back-up, bearing assemblies. For example, in many satellite and spacecraft applications, the flywheel system may include one or more magnetic bearing assemblies that function as the primary bearing assemblies, and one or more mechanical bearing assemblies that function as the secondary bearing assemblies.
The rotating group in an energy storage flywheel system may rotate at several thousand revolutions per minute (rpm) during operation. For example, in some applications, the rotating group may reach rotational speeds of up to 100,000 rpm. As a result, the rotating group may experience relatively high centrifugal stresses during rotation. These relatively high centrifugal stresses may, in some highly unlikely instances, cause the rotating group to suffer a structural failure while rotating at high rotational speed. This in turn may result in high-speed fragments being thrown from the rotating group. These high-speed fragments could present a hazard to surrounding systems and components, as well as to persons that may be in the vicinity. In addition, if such an unlikely failure were to occur while testing a flywheel rotor that is constructed of a composite material, such as filament wound carbon fiber, individual fibers can be thrown from the flywheel. These fibers can have sufficient energy to ignite and generate plasma.
Thus, before placing an energy storage flywheel system into service, the system, or at least the rotating group, undergo certification testing at full speed to ensure the rotating group can withstand the centrifugal forces at full speed. When an energy storage flywheel system, or at least the rotating group, is being certification tested, the components under test may be placed in a containment vessel. The containment vessel is preferably designed to contain any high-speed fragments that could potentially result from an unlikely structural failure of the rotating group while rotating at full speed.
Although presently known containment vessels are generally safe and reliable, these known vessels do suffer certain drawbacks. For example, many vessels are susceptible to undesirable vibration during flywheel system testing, and/or are not designed to fully contain all the high-speed fragments and/or plasma that may be generated during a highly unlikely failure during testing.
Hence, there is a need for a containment vessel that improves on one or more of the above-noted drawbacks. Namely, a containment vessel that is configured to damp undesirable vibration during flywheel system testing, and/or to fully contain all the high-speed fragments and/or plasma that may be generated during a highly unlikely failure during testing. The present invention addresses one or more of these needs.